Silent chain and method of assembly thereof

ABSTRACT

A silent chain is disclosed in which sets of intermeshing links are connected together by means of pins received in front and rear openings in the links between two segmental bushings. Each segmental bushing is rigidly secured in the openings of one of the sets of links to form an inflexible link and bushing unit. Adjacent rigid link and bushing units pivot on each pin to provide flexibility of the chain without play or wear between the bushing segments and the links.

United States Patent Avramidis [451 May 9,1972

[54] SILENT CHAIN AND METHOD OF ASSEMBLY THEREOF [72] Inventor: StelliosAntony Avramidis, Greenfield,

Ind.

[73] Assignee: FMC Corporation, San Jose, Calif. [22] Filed: May 25,1970 [2 l] Appl. No.: 40,030

[52] [1.5. CI. ..74/245 S [51] Int. Cl. ..Fl6g 13/02 [58] Field ofSearch ..74/245 S, 255

[56] References Cited UNlTED STATES PATENTS 2,047,833 7/1936 Pierce..74/255 S X 953,429 3/1910 Morse ..74/255 S 1,027,002 5/1912 Richmond..74/255 S 1,306,078 6/1919 Renold et al.. ..74/255 S 1,743,500 1/1930Sturtevant.... ..74/245 5 X 2,101,341 12/1937 Perry 74/255 S PrimaryExaminer-Leonard H. Gerin Attorney-F. W. Anderson, C. E. Tripp and J. F.Verhoeven [5 7] ABSTRACT A silent chain is disclosed in which sets ofintermeshing links are connected together by means of pins received infront and rear openings in the links between two segmental bushings.Each segmental bushing is rigidly secured in the openings of one of thesets of links to form an inflexible link and bushing unit. Adjacentrigid link and bushing units pivot on each pin to provide flexibility ofthe chain without play or wear between the bushing segments and thelinks.

4 Claims, 5 Drawing Figures PATENTED AY 91972 SHEET 1 BF 2 F'II3 1 6 m um Tu my m NT W IN L v w? Y B ATTORNEYS BACKGROUND OF THE INVENTION Thepresent invention relates to silent chains and, more particularly, to aconstruction, and method of assembling, silent chains to reduce play inthe chain and thereby reduce wear of elements of the chain.

A typical silent chain is a chain (which may, for example, be an endlessdrive chain) that is constructed of leaf links having inwardly extendingteeth. The chain teeth mesh with the outwardly extending teeth of asprocket which extends the full width of the chain. The chain linksengage the teeth of the sprocket and the inner sides of the links areshaped for this engagement. The links are held together by pins receivedthrough front and rear openings in the links, and frequently the pinsare received between segmental bushings also received through the linkopenings as shown in the patent to Oakes, U.S. Pat. No. 1,419,891.

Any play or looseness between the links and the bushings will increasewear on these elements of the chain. This wear, in turn, will increasethe looseness between the chain elements. Any significant wear willincrease the pitch of the chain and cause an elongation of the chain toimpair satisfactory mating of the chain with the sprocket.

SUMMARY OF THE INVENTION The silent chain of the present invention hasreduced play and looseness to minimize wear of the chain elements. Inthe preferred form of the present invention, each set of links of thesilent chain is received in intermeshing relationship with adjacent setsof links of the chain. Each link of each set of links has a front and arear opening with pockets formed in the outer edge of each opening. Afront and a rear segmental bushing are tightly received, respectively,in the front and rear pockets of all the links of a set to form a rigidlink and bushing unit. The front segmental bushing also passes throughthe rear openings of one adjacent set of links and the rear segmentalbushing passes through the front openings of the other adjacent set oflinks. Pins are received in the openings between the bushings to coupleadjacent rigid link and bushing units together. When tension is appliedto the chain, force is transmitted from the pin in the front opening tothe front segmental bushing rigidly secured in the link, through thelink to the rear segmental bushing rigidly secured in the link, to thepin in the rear opening. With no play or looseness between the link andthe two segmental bushings secured therein, a minimum of play ispossible between the pins. Thus, the wear of the chain is reduced andthe tendency of the chain to elongate is diminished. Tests haveindicated that wear of some elements of the chain of the presentinvention are as much as 50 percent less than chains without rigid linkand bushing units.

It is therefore one object of the present invention to provide a silentchain with minimum play therein.

It is another object of the present invention to provide a silent chainwith reduced tendency to wear.

It is yet another object of the present invention to provide a silentchain which resists elongation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in perspective of thesilent chain of the present invention mounted on a sprocket.

FIG. 2 is a view in plan, with parts broken away, of the chain of FIG.1.

FIG. 3 is a view taken on the line 3-3 of FIG. 2.

FIG. 4 is a fragmentary view in perspective of adjacent links of thechain of FIG. 1 showing portions of the elements connecting the linkstogether.

FIG. 5 is a side view in elevation of a link to show the front and rearopenings therein without the bushings and pins in the openings.

DESCRIPTION OF THE PREFERRED EMBODIMENT There is shown in FIG. 1 asilent chain, indicated generally at 10, mounted on two spaced sprockets12 and 14. The sprockets have outwardly extending teeth 16, which, asindicated at 18, are interrupted in the center to receive guide links 20in the chain. The chain 10, which is endless, has inwardly extendingteeth 22 which mesh with the teeth 16 of the sprockets l2 and 14.

The teeth 22 are an integral part of links 24, as shown best in FIG. 3.Some of the links 24 consist of two link sections 24a and 24b which areidentical and contiguous in side-by-side relation. Each link has anopening at each end which may, for convenience, be designated a forwardopening 26 and a rear opening 28 merely to distinguish between theopenings in the description of the invention and not necessarily toindicate the direction of movement of the chain. Each opening has apocket 30 formed in the outer edge of the opening (that is, the pocketis formed in the forward edge of the forward opening and in the rearedge of the rear opening).

A first set 8-1 of links, which are aligned in laterally spacedrelation, has a front segmental bushing FSB-l (FIG. 3) tightly andrigidly secured in the pockets of the front openings in all the links ofthe set. The set 8-] of links also has a rear segmental bushing RSB-ltightly and rigidly secured in the pockets of the rear openings in allthe links of the set. The segmental bushings are preferably slightlylarger than the pockets and pressed therein. When the two segmentalbushings are pressed into the pockets of the front and rear openings,respectively, a rigid inflexible link and bushing unit is formedcomprising all the links 24 of set S-1 and the bushings FSB-l andRSB-1.'

A second set S2 of links consists of aligned, laterally spaced apartlinks 24 identical to the links of set 8-1. A rear segmental bushingRSB-2, identical to bushing RSB-l, extends through the front openings inthe links of set S-1 and through the rear openings in the links of set8-2. The bushing RSB-2 which is also slightly larger than the pockets ofthe rear openings of the links of set S2, is tightly and rigidly pressedinto those openings. A front segmental bushing FSB-2 is tightly receivedin the pocket of the front openings in the set S2 of links 24. The linksof set S2, and the two bushings RSB-2 and FSB-2 tightly receivedtherein, form a inflexible link and bushing unit. It will be noted that,for convenience, the segmental bushings tightly received in a set oflinks has been given a digital suffix similar to the digital suffixgiven to the set of links.

A third set of links 8-3 also consists of aligned, laterally spacedapart links 24 identical to the links of sets 8-] and S2. The frontsegmental bushing FSB-3 of the set of links 8-3 extends through the rearopenings of the links of set S-1 and the rear segmental bushing RSB-l ofthe set of links S-l extends through the front openings of the set oflinks 8-3.

The sets S2 and 8-3 of links are interconnected by segmental bushingswith other adjacent sets of links in the same manner they areinterconnected with the set of links 5-]. Additional sets of links areconnected seriatim to form the endless chain 10.

The pivotal connection between the inflexible link and bushing units isformed by a pin 34 received in the aligned openings of adjacent sets oflinks (that is, the front openings of one set of links, such as S-l, andthe rear openings of the next forward adjacent set of links S2) betweenthe segmental bushings of the respective sets of links. At each openingof each link of the set, say the front opening of a link 24 of the setof links 8-], the pin on one side (the forward side of the pin in theforward opening of a link) will be engaged with the forward segmentalbushing FSB-l tightly secured, with no clearance or play, in the pocketof the opening. On the opposite side of the pin (the rear side of thepin in the forward opening of a link) the pin is engaged with the rearsegmental bushing RSB-2 of the next forward set of links S2. The rearsurfaceof the bushing RSB-2 engages, but not tightly, the rear surfaceof the forward opening in the link of set 3-1. The pin,

at each end, is of reduced diameter and extends through washers 35. Theends of the pins are peened over the washers to hold the pin in thelinks.

In each link 24, the edge 40 of each opening opposite the pocket 30 issemi-circular with a radius larger than the radius of the pin to permitreceipt of the segmental bushing between said edge and the pin. Smallportions 42 of the inner surface of the openings lie on circles of aradius slightly larger than the radius of the pin. The segmentalbushings have a concave inner surface 44 of circular conformation formating engagement with the pin. The bushings have a rear convex surface46 in the conformation of a wide V. The pockets have inner surfaces 48mating tightly with the rear surfaces of the bushings.

Although the rear surfaces of the bushings tightly received in thepockets are pressed against the pocket surfaces, as at 50, the rearsurfaces of the bushings received in the link openings opposite thepockets are not tightly pressed against the circular opening edge 40, asat 52, so that pivotal action between adjacent sets of pins can occur.The rear V-shaped surface of the segmental bushing shown to illustratethe present invention has three surfaces 54, 56, and 58 which normallymake contact with the edge surface 40 when the chain is unloaded. Itshould be noted that in FIG. 2 there is shown a clearance, exaggeratedfor clarity of illustration only, between contact surface 56 and openingsurface 40. This clearance, which may be small or nonexistent when thechain is unloaded, is greater when the chain is loaded. Similarclearances occur between the bushing end surfaces 54, 58 and the linkopening surface 40. Although a segmental bushing with a V- shaped backhas been illustrated, the back could very well be circular, oval, or ofother geometrical configuration. At least one end of each bushing ischamfered, as indicated at 60, to facilitate pressing the bushing intothe pockets of the links.

When any segment of the chain is under tension during use, the forcetransmitted through the chain is transmitted through structure with aminimum of play or looseness to keep the wear of the chain at a minimum.Force is transmitted from one pin to a segmental bushing secured rigidlyin a pocket 30 in one of the openings of the set of links. From thebushing in the pockets, the force is transmitted through the set oflinks to the other bushing tightly secured in the pockets of the otheropenings in said set of links. From this bushing, the force istransmitted directly to the pin.

Although the best mode contemplated for carrying out the presentinvention has been herein shown and described, it will be apparent thatmodification and variation may be made without departing from what isregarded to be the subject matter of the invention.

What is claimed is:

l. A silent chain comprising 1. a plurality of inflexible link andbushing units, each inflexible link and bushing unit comprising a. aplurality of links having openings at each end,

b. a first segmental bushing rigidly secured in each of said openings inone end of the links,

c. and a second segmental bushing rigidly secured in each of saidopenings in the other end of the links, the bushings of adjacent linkand bushing units received in the openings at each end of the links andthe links of adjacent link and bushing units received in intermeshingrelationship with the links,

2. and pins received through the openings and between the segmentalbushings of adjacent inflexible link and bushing units to pivotallyconnect said units together.

2. A silent chain comprising 1. a first inflexible link and bushing unitcomprising a. a plurality of links each having a front and rear openb. afront segmental bushing secured in the front openings of the links and arear segmental bushing secured in the rear openings of the links to forman inflexible link and bushing unit with the links in spaced relation,

2. a second inflexible link and bushing unit similar to said firstinflexible link and bushing unit, 3. a pin extending through the rearopenings of the links of said second inflexible link and bushing unitand through the front openings of the links of said first inflexiblelink and bushing unit,

4. a third inflexible link and bushing unit similar to said first andsecond inflexible link and bushing unit, the segmental bushing of saidthird inflexible link and bushing unit extending through the rearopenings of said first link and bushing unit,

5. a pin extending through the front openings of the links of said thirdinflexible link and bushing unit and through the rear openings of saidfirst inflexible link and bushing unit, and

6. a plurality of additional inflexible link and bushing units connectedseriatim to said second and third inflexible link and bushing units.

3. A silent chain comprising 1. a first inflexible link and bushing unitcomprising a. a plurality of links each having a front and rear opening,each opening including a pocket in the outer edge of the opening,

b. a front segmental bushing rigidly pressed into the pockets of thefront opening and a rear segmental bushing rigidly pressed into thepockets of the rear openings, to form an inflexible link and bushingunit with the links in spaced relation,

2. a second inflexible link and bushing unit similar to said firstinflexible link and bushing unit, the rear segmental bushing of saidsecond inflexible link and bushing unit received through the frontopenings of said first inflexible link and bushing unit and the frontsegmental bushing of said first inflexible link and bushing unitreceived through the rear openings of said second inflexible link andbushing unit,

3. a third inflexible link and bushing unit similar to said first andsecond inflexible link and bushing unit, the front segmental bushing ofsaid third inflexible link and bushing unit received through the rearopenings of said first inflexible link and bushing unit and the rearsegmental bushing of said first link and bushing unit received throughthe front openings of said third inflexible link and bushing unit,

4. additional inflexible link and bushing units connected, respectively,to said second and third inflexible link and bushing units in series,the links of all of the inflexible link and bushing units including saidfirst, second, and third units received in intermeshing relationshipwith the links of adjacent units, and

5. a pin received through each opening between the segmental bushingstherein to pivotally connect adjacent inflexible link and bushing units.

4. A silent chain comprising a plurality of sets of aligned links, eachset having a segmental bushing rigidly secured in each end to form withsaid set an inflexible link and bushing unit, each segmental bushing ofeach unit receiving links of an adjacent unit thereon, and a pinreceived between the segmental bushings of adjacent units to form apivotal connection between the inflexible link and bushing units.

1. A silent chain comprising
 1. a plurality of inflexible link andbushing units, each inflexible link and bushing unit comprising a. aplurality of links having openings at each end, b. a first segmentalbushing rigidly secured in each of said openings in one end of thelinks, c. and a second segmental bushing rigidly secured in each of saidopenings in the other end of the links, the bushings of adjacent linkand bushing units received in the openings at each end of the links andthe links of adjacent link and bushing units received in intermeshingrelationship with the links,
 2. and pins received through the openingsand between the segmental bushings of adjacent inflexible link andbushing units to pivotally connect said units together.
 2. and pinsreceived through the openings and between the segmental bushings ofadjacent inflexible link and bushing units to pivotally connect saidunits together.
 2. A silent chain comprising
 2. a second inflexible linkand bushing unit similar to said first inflexible link and bushing unit,2. a second inflexible link and bushing unit similar to said firstinflexible link and bushing unit, the rear segmental bushing of saidsecond inflexible link and bushing unit received through the frontopenings of said first inflexible link and bushing unit and the frontsegmental bushing of said first inflexible link and bushing unitreceived through the rear openings of said second inflexible link andbushing unit,
 3. a third inflexible link and bushing unit similar tosaid first and second inflexible link and bushing unit, the frontsegmental bushing of said third inflexible link and bushing unitreceived through the rear openings of said first inflexible link andbushing unit and the rear segmental bushing of said first link andbushing unit received through the front openings of said thirdinflexible link and bushing unit,
 3. A silent chain comprising
 3. a pinextending through the rear openings of the links of said secondinflexible link and bushing unit and through the front openings of thelinks of said first inflexible link and bushing unit,
 4. a thirdinflexible link and bushing unit similar to said first and secondinflexible link and bushing unit, the segmental bushing of said thirdinflexible link and bushing unit extending through the rear openings ofsaid first link and bushing unit,
 4. A silent chain comprising aplurality of sets of aligned links, each set having a segmental bushingrigidly secured in each end to form with said set an inflexible link andbushing unit, each segmental bushing of each unit receiving links of anadjacent unit thereon, and a pin received between the segmental bushingsof adjacent units to form a pivotal connection between the inflexiblelink and bushing units.
 4. additional inflexible link and bushing unitsconnected, respectively, to said second and third inflexible link andbushing units in series, the links of all of the inflexible link andbushing units including said first, second, and third units received inintermeshing relationship with the links of adjacent units, and
 5. a pinreceived through each opening between the segmental bushings therein topivotally connect adjacent inflexible link and bushing units.
 5. a pinextending through the front openings of the links of said thirdinflexible link and bushing unit and through the rear openings of saidfirst inflexible link and bushing unit, and
 6. a plurality of additionalinflexible link and bushing units connected seriatim to said second andthird inflexible link and bushing units.